ORS 537.099 requires federal and state agencies, cities, counties, schools, irrigation districts and other special districts to annually report their water use. Beginning in the early 1990s, many water use permits issued to non-governmental users include a water measurement and an annual reporting requirement.
OAR 690-085 describes the procedures and requirements for reporting, and specifies that reports of monthly use shall be submitted for each diversion at the end of each water year, which is September 30.